Sewage disposal . ately high, some measure of automatic control is al-most an essential; although the necessity for occasional expertsupervision should in no case be forgotten. The distribution of sewage in small contact beds requires nospecial provision. In large installations surface troughs are oftenprovided to avoid lateral filling. At Manchester the sewage isdischarged in radiating surface channels lined with fine screen- RESULTS OF CONTACT TREATMENT 285 ings, which retain the bulk of the suspended matter and thusprolong the life of the beds themselves (Fig. 78). At Plainfield, N. J., and
Sewage disposal . ately high, some measure of automatic control is al-most an essential; although the necessity for occasional expertsupervision should in no case be forgotten. The distribution of sewage in small contact beds requires nospecial provision. In large installations surface troughs are oftenprovided to avoid lateral filling. At Manchester the sewage isdischarged in radiating surface channels lined with fine screen- RESULTS OF CONTACT TREATMENT 285 ings, which retain the bulk of the suspended matter and thusprolong the life of the beds themselves (Fig. 78). At Plainfield, N. J., and at Ballston Spa, N. Y., the sewagewas at first delivered through one-half foot pipes laid about onefoot below the surface (Fig. 79). Using this method the surfaceof the bed remains clean, and there is less danger of a nuisancebeing created from odors, or of pathogenic bacteria being car-ried away from the beds by winged insects. Fuller (1912) car-ries this same principle further by filling contact beds from below. Fig. 79. Distribution of Sewage on Contact Beds at Plainfield, N. J.(courtesy of F. E. Daniels). through a false bottom, never permitting the liquid to rise towithin 6 inches of the surface. The primary beds at Plainfieldhave been filled in this way since 1910. Results of Contact Treatment. In appearance the contacteffluent is fairly clear, but usually rather dark in color. In re-gard to chemical composition, the purification effected by singleand double contact treatment is fairly represented by the datacollected from various sources and tabulated and plotted indiagrammatic form by Winslow and Phelps (1906) (Fig. 80).The first contact removes somewhat more than half of the or-ganic constituents of the sewage, as measured by oxygen con-sumed and albuminoid nitrogen, and two-thirds or more of thesuspended solids, while the second contact effects almost as great 286 TREATMENT OF SEWAGE IN CONTACT BEDS 3 H n 3 Eh< S _ oE- 2 o - eh-s- *l OPh 0 s & pa .2S ap eB a j ?|
Size: 2055px × 1216px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublisherlondo, bookyear1919
